Garuda - Garba Rujukan Digital

All

ASEAN Journal on Science and Technology for Development

ajstd
Website

Published by Universitas Gadjah Mada

ISSN : 22249028 EISSN : 22249028 DOI : -

Core Subject : Science, Education, Engineering,

Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Mathematics

The coverage is focused on, but not limited to, the main areas of activity of ASEAN COST, namely: Biotechnology, Non-Conventional Energy Research, Materials Science and Technology, Marine Sciences, Meteorology and Geophysics, Food Science and Technology, Microelectronics and Information Technology, Space Applications, and Science and Technology Policy, Infrastructure and Resources Development.

Arjuna Subject : -

Articles 10 Documents

Search results for , issue "Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)" : 10 Documents clear

Application of Deswirl Device in Cyclone Dust Separator M. Z. Abdullah; Z. Husain; S. M. Fraser
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

The experimental investigations of the vortex flow inside the vortex finder (outlet duct) of the cyclone dust separator have been carried out. Preliminary study from the visualization experiment has been performed and discovered vortex instability inside the conventional vortex finder. In order to minimize the instabilities, the streamlined entry shape was inserted at the vortex finder entrance and the results showed remarkable improvement of the vortex flow instability inside the vortex finder. The velocity measurements of two main components of velocity were performed using a laser-Doppler anemometry at the cyclone vortex finder outlet. The experiments were conducted at a constant flow rate of 0.0246m3/s with the vortex finder diameter of 64mm and with several types of entrance configuration in order to improve the cyclone performance and to reduce the losses. The use of deswirl devices inside the vortex finder significantly reduced pressure drop and energy losses.

Design and Development of A Three-Point Auto Hitch Dynamometer for An Agricultural Tractor A. F. Kheiralla; A. Yahya; M. Zohadie; W. Ishak
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

This paper describes the design, development and calibration of a three-point auto hitch dynamometer for measuring the horizontal and vertical forces that existed at the three-point hitch of an agricultural tractor. The design concept of the dynamometer was based on an instrumented inverted U frame assembly that was mounted between tractor links and implement. The design incorporates for both lower point hitch spread and mast height adjustments, and quick hitch capability in accordance with category 1 and II three-point hitch system. The force sensing elements were comprised of three steel extended octagonal ring transducers that were located between the inverted U frame and hook brackets. Electrical resistance strain gauges were mounted on the extended octagonal ring transducer at strain angle nodes to independently monitor strains that were proportional to the horizontal and vertical forces at the ring center. Each transducer was designed for maximum horizontal and vertical forces of 25 kN and 10 kN at measurement mean sensitivities of 25.19 µStrain/kN and 25.60 µStrain/kN, respectively. However, the complete dynamometer has been designed to measure the maximum resultant horizontal and vertical forces of 50 kN and 20 kN, respectively. Field demonstration tests on the dynamometer and data acquisition system showed that they were able to function effectively as intended. The data acquisition system was able to successfully scan and record the dynamometer signals as programmed. This dynamometer was part of the complete instrumentation system to be developed onboard a Massey Ferguson 3060 tractor for the generation of a comprehensive database on the power and energy requirements of the tractor and its working implement in the field.

Design of A Hvdc-Based Controller for Load Change Compensation and Stabilization of Inter-Area Oscillations I. Ngamroo
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

As an interconnected power system via a High-Voltage Direct Current (HVDC) link is subjected to a rapid load change with the frequency of inter-area oscillation mode, system frequency and tie line power may be severely disturbed and oscillate. To compensate for the rapid load change and stabilize both frequency and tie line power oscillations due to the inter-area mode, the dynamic power flow control via a HVDC link can be exploited. To implement this concept, a new design method of HVDC-based controller is proposed. To grasp a physical characteristic of the inter-area oscillation frequency, the technique of overlapping decompositions is employed to achieve the subsystem embedded with the inter-area mode. Consequently, the second-order lead/lag controller of HVDC link can be designed in this subsystem. To acquire the desired overshoot of frequency oscillations, the parameters of the controller are automatically optimized by the Tabu Search (TS) algorithm. The effectiveness of the designed controller is investigated in a three-area longitudinal interconnected power system which represents the interconnection between the south of Thailand and Malaysia power systems.

Effect of Substrate Feeding Concentration on Initial Biofilm Development in Anaerobic Hybrid Reactor B. Suraraksa; A. Nopharatana; P. Chaiprasert; S. Bhumiratana; M. Tanticharoen
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

To elucidate the effect of substrate concentration on biofilm development, glucose concentrations of 500 and 1,000 mg/L were used. At an early stage, biofilm development at both concentrations was not significantly different (P=0.621). After removing suspended biomass at 24 operational hours, the biofilm development at high substrate concentration was higher than at lower concentration. At 72 operational hours, the amounts of attached biomass at low and high glucose feeding were 9.04±1.17 and 28.58±2.72 g VSS/m2, respectively. The activities of acidogens, acetogens, and methanogens at the low glucose concentration were 0.334, 0.016 and 0.003 g COD/g VSS/h, and those at the high glucose concentration were 0.145, 0.003 and 0.001 g COD/g VSS/h, respectively. Moreover, the ratio of methanogenic activity at low glucose concentration was higher than at high glucose concentration. The glucose utilization at low and high feeding concentrations was 33% and 27%, respectively. These results indicated that rapid biofilm development by using high substrate concentration would be less beneficial if unbalance of methanogenic ratio was found in biofilm.

Efficient Reactive Power Compensation Algorithm for Distribution Network J. Jerome
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

The use of automation and energy efficient equipment with electronic control would greatly improve industrial production. These new devices are more sensitive to supply voltage deviation and the characteristics of the power system that was previously ignored are now very important. Hence the benefits of distribution automation have been widely acknowledged in recent years. This paper proposes an efficient load flow solution technique extended to find optimum location for reactive power compensation and network reconfiguration for planning and day-to-day operation of distribution networks. This is required as a part of the distribution automation system (DAS) for taking various control and operation decisions. The method exploits the radial nature of the network and uses forward and backward propagation technique to calculate branch currents and node voltages. The proposed method has been tested to analyze several practical distribution networks of various voltage levels and also having high R/X ratio.

Empirical Models for Power and Energy Requirements II : A Powered Implement Operation in Serdang Sandy Clay Loam, Malaysia A. F. Kheiralla; A. Yahya; M. Zohadie; W. Ishak
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Power and energy requirements were measured with an instrumented tractor for rotary tilling in Serdang sandy clay loam soil. The effects of travel speed and rotor speed upon the measured data were investigated. Power model from orthogonal regression analysis was formulated based on linear and quadratic functions of travel speed and bite length. Fuel consumption model from regression analysis was formulated based on linear tractor PTO power as well as linear equivalent tractor PTO power. Fuel consumption rates predicted by ASAE D497.3 were found to be 25% to 28% overestimates of the values predicted by the model developed. However, fuel consumption rates reported by OECD Tractor Test were found to be 1% to 9% lower than the fuel consumption rates predicted by the model developed. A comparison of power and energy requirements for both powered and draught implements showed that the disk harrow was the most energy efficient implement in terms of fuel consumption and specific energy followed by the rotary tiller, disk plough and mouldboard. Finally, average PTO power, fuel consumption, wheel slip, wheel power and specific energy for a powered implement are presented.

Genetic Diversity of Introduced (Pomacea canaliculata) and Native (PILA) Apple Snails in Thailand Revealed by Randomly Amplified Polymorphic DNA (RAPD) Analysis B. Thaewnon-ngiw; S. Klinbunga; K. Phanwichien; N. Sangduen; N. Lauhachinda; P. Menasveta
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Genetic diversity of the introduced golden apple snail, Pomacea canaliculata (Lamarck, 1822) and four native apple snails; Pila ampullacea (Linneaus, 1758), P. angelica (Annandale, 1920), P. pesmei (Morelet, 1889) and P. polita (Deshayes, 1830) in Thailand were studied by RAPD analysis. Two hundred and two polymorphic fragments (180-1500 bp in length) were generated across overall investigated samples (N = 254) using three informative primers (OPA07, OPB10 and UBC122). The percentages of polymorphic bands were 98.86%, 94.56%, 90.91%, 96.94% and 95.51% for Pomacea canaliculata, P. ampullacea, P. angelica, P. pesmei and P. polita, respectively. This indicated high genetic polymorphism of these taxa. A neighbor-joining tree between pairs of geographic samples within Pomacea canaliculata suggested a lack of phylogeography in this species. Moreover, candidate species-specific RAPD markers (pKUSCARPILA-F/R) found in Pomacea canaliculata (340 bp, OPB10), P. ampullcea (640 bp, OPA07), P. angelica (380 bp, UBC122) and Pila snails (430 bp, OPA07) were cloned and sequenced. Locus-specific primers were designed and tested against the target and nontarget species. A 259 bp SCAR marker was found in 95.0% of Pila apple snails (N = 163) but not in Pomacea canaliculata (N = 30). Therefore, this SCAR marker could be used in coupling with a Pomacea canaliculata-specific RAPD marker to unambiguously differentiate the introduced and native apple snails in Thailand.

The Use of Artificial Neural Network to Optimize The pH Response Range of Chlorophenol Red F. Wong; M. Ahmad; L. Y. Heng
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Artificial Neural Network (ANN) had been used in this study to extend the response range of the pH indicator. The input from absorbance values of the absorbance spectra of chlorophenol red at different pH was used to train the ANN. During the training process, the coefficient values of the ANN will be adjusted to obtain the desire output. In this research, back propagation algorithm had been used for optimizing the response range of the pH indicator chlorophenol red in solution. The result indicates that the use of ANN enable the pH response range to be extended from 4.8-6.8 to 1.0-10.0.

Entropy Learning in Neural Network Geok See Ng; D. Shi; A. Wahab; H. Singh
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

In this paper, entropy term is used in the learning phase of a neural network. As learning progresses, more hidden nodes get into saturation. The early creation of such hidden nodes may impair generalisation. Hence entropy approach is proposed to dampen the early creation of such nodes. The entropy learning also helps to increase the importance of relevant nodes while dampening the less important nodes. At the end of learning, the less important nodes can then be eliminated to reduce the memory requirements of the neural network.

Extraction of Residue Oil from Palm Oil Mill Effluent (POME) Using Organic Solvent A. L. Ahmad; K. Sithamparam; M. M. D. Zulkali; S. Ismail
ASEAN Journal on Science and Technology for Development Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Palm oil industry in Malaysia has grown to become an important agriculture based industry and it is accounted for about 52% of the world palm oil output, which generated RM 13 billions export earning for the country. With increased cultivation and production of palm oil in the region, the disposal of the processed waste will become a major problem if it is not being treated properly. Palm oil mill effluent (POME) is extremely polluting with its high organic content. Oil and grease content in POME is 4,000 mg/L which is relatively high compared to the allowable limit by the Malaysian Department of Environment of only 50 mg/L. This paper describes the research results in removing oil and grease content for the POME using solvent extraction method. Six different organic solvents; n-hexane, n-heptane, benzene, petroleum ether, pentane and petroleum benzene were used. For every solvent the effect of solvent ratio, mixing time, mixing speed and pH were analyzed to determine the optimum condition for maximum extraction of oil. Results showed that n-hexane give the best performance in extracting oil from POME with solvent to POME ratio of 6:10. It was estimated about 0.54 grams of oil and grease per liter of POME can be extracted at optimum conditions; mixing speed of 200 rpm, 20 minutes mixing time and at pH 9.

Page 1 of 1 | Total Record : 10

Filter by Year

2003 2003

Filter By Issues

All Issue Vol. 39 No. 3 (2022): Land, Energy, and Water Resources Vol. 39 No. 2 (2022): Green Economy Vol. 39 No. 1 (2022): Community Resilience Vol. 38 No. 3 (2021): Embrace Potential Vol. 38 No. 2 (2021): Repurpose & Redefine Vol. 38 No. 1 (2021): A New Perspective on Development Vol. 37 No. 3 (2020): Movement Vol. 37 No. 2 (2020): The Perennial Quest Vol. 37 No. 1 (2020): Earth, Water & Fire Vol. 36 No. 1 (2019): Vol 36 No 1 (2019) Vol. 36 No. 3 (2019): Ahead of the Storm Vol. 36 No. 2 (2019): Across the Archipelago Vol. 35 No. 1-2 (2018): Extent of transfer of alien invasive organisms in South/Southeast Asia regio Vol. 35 No. 3 (2018): Developments in Nuclear Techniques in the Treatment of Cancer Vol. 34 No. 2 (2017): Vol 34 No 2 (2017) Vol. 34 No. 1 (2017): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 33 No. 2 (2016): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 33 No. 1 (2016): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 32 No. 2 (2015): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 32 No. 1 (2015): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 31 No. 2 (2014): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 31 No. 1 (2014): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 30 No. 1-2 (2013): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 29 No. 2 (2012): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 29 No. 1 (2012): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 28 No. 2 (2011): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 27 No. 1 (2010): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 26 No. 1 (2009): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 25 No. 2 (2008): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 25 No. 1 (2008): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 24 No. 1-2 (2007): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 24 No. 4 (2007): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 1-2 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 4 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 3 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 22 No. 4 (2005): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 21 No. 1 (2004): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 20 No. 1 (2003): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 18 No. 1 (2001): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 17 No. 2 (2000): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 17 No. 1 (2000): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 10 No. 2 (1993): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 8 No. 2 (1991): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 7 No. 1 (1990): ASEAN Journal on Science and Technology for Development Vol. 5 No. 2 (1988): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 5 No. 1 (1988): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 4 No. 2 (1987): Vol. 4 No. 2 (1987) Vol. 4 No. 1 (1987): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 3 No. 1 (1986): Vol. 3 No. 1 (1986) Vol. 2 No. 1 (1985): Vol. 2 No. 1 (1985) Vol. 1 No. 1 (1984): Vol. 1 No. 1 (1984) More Issue

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name -

Contact Email -

Phone -

Journal Mail Official -

Editorial Address -

Location Kab. sleman, Daerah istimewa yogyakarta INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA